Beijing's average PM2.5 index of 91.6 micrograms per cubic meter in first half of 2014 represents an 11.2 percent year-on-year decrease.

The airborne particles smaller than 2.5 microns in diameter are blamed for Beijing's notorious smog and the figure is still far above the national standard of 35 micrograms per cubic meter, said the report by Beijing Municipal Environmental Protection Bureau.

In first half 2014, the density of other major pollutants such as PM10, SO2 and NO2 has also fallen in the capital. Heavy pollution days also dropped from 40 in the first half of 2013 to 25 this year.

In Sept. 2013, a five-year plan was introduced to slash coal consumption, promote clean energy use and reducing production capacities of heavy polluters. Endi